This invention relates to electrical assemblies which generate heat and which are contained within an enclosure and, more particularly, to structure for dissipating heat from such assemblies.
An electrical assembly utilized as a base station for a cellular telephone system is typically mounted outdoors, where it is exposed to the environment. Such an assembly includes heat generating components and is mounted within an enclosure, and therefore some means for dissipating the heat must be provided. In addition, such an assembly is usually provided with an outer cover which acts as a solar shield and which is beneficial in sheltering the unit from solar heat, but such a cover can impede the dissipation of heat from the assembly. It is known to provide a heat sink including heat conducting fins on the enclosure under the solar shield for dissipating heat generated within the enclosure. These fins are typically planar and parallel to define vertical channels between adjacent pairs of the fins. The vertical channels act as chimneys which allow heated air to rise and escape through appropriate openings at the top of the shield. However, air which is heated by the fins at the bottom of a chimney and travels to the top of the chimney has more and more heat added to it as it travels upward, thereby adversely impacting heat transfer near the top of the assembly. It would therefore be desirable to provide structure which does not suffer from this disadvantage.